GC/MS Investigation of the Reaction Products of Nitrogen Mustards and N,N-Dialkylaminoethyl-2-Chlorides With Phenol

The Chemical Weapons Convention (CWC)–scheduled chemicals that contain chlorine atom (e.g., mustards, aminoethyl-2-chlorides, and phosphorylchlorides) are highly reactive in environmental matrices, especially when they are in contact with phenols, for example, in the decontamination process. In such a case, these scheduled chemicals are converted to corresponding phenyl ethers/esters, which are referred to as the reaction products. The detection and identification of any reaction products of CWC chemicals are crucial markers for verification processes, and they provide a clue to the alleged use or presence of the parent CWC scheduled chemicals. In this study, a series of reaction products of nitrogen mustards (HN1, HN2, and HN3) with phenol (1–3) and N,N-dialkylaminoethyl-2-chlorides with phenol (4–13) were synthesized using respective aminoethyl-2-bromides as intermediates and subsequently analyzed the products, phenyl ethers (1–13) by GC-EIMS and GC-CIMS. The GC/EI spectra of 1–13 exhibited M⁺· ions and distinctive structure indicative fragment ions. The selective fragmentation of the alkyl groups attached to nitrogen facilitated the discrimination of possible isomeric compounds. The primary fragmentation of 1–13 was C-C bond cleavage (α-carbon with respect to the nitrogen) gave rise to [M-C₇H₇O]⁺ ion as the base peak. GC/CI (methane) spectra included abundant [M + H]⁺ ion, reagent-specific adduct ions, and a few structure-indicative fragment ions. The GC retention index (GC/RI) values of 1–13 were calculated using a hydrocarbon mixture, and these values were higher than those of the corresponding reported GC/RI values of nitrogen mustards/N,N-dialkylaminoethyl-2-chlorides. The GC/MS and GC/RI data provide critical insights for the unambiguous identification of the targeted reaction products, which are essential for effective verification under the CWC and help in the participation of official proficiency tests conducted by the Organization for the Prohibition of Chemical Weapons.